Integrated circuit devices are often designed to operate portions of their circuitry using voltages different than the supply voltages (e.g., reference voltages, core voltages, ground potential, etc.). These non-standard voltages may be generated internally, such as through the use of charge pumps. Charge pumps are circuits that are used to generate a “pumped voltage” having a magnitude that is larger than the magnitude of its supply voltage.
Memory devices are common integrated circuit devices. Memory devices are typically provided as internal, semiconductor, integrated circuit devices in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and flash memory.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the memory cells, through programming (which is often referred to as writing) of data-storage structures, using charge-storage structures (e.g., floating gates or charge traps) or other physical phenomena (e.g., phase change or polarization), determine the data state of each cell. Common uses for flash memory include personal computers, personal digital assistants (PDAs), digital cameras, digital media players, cellular telephones, solid state drives and removable memory modules, and the uses are growing. A memory device typically utilizes a wide variety of non-standard voltages for the effective and efficient access of its memory cells, such as reading, programming or erasing these memory cells. These voltages may change throughout the life-cycle of the memory device due to age and/or operating conditions of the memory device, for example.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative apparatus and methods for voltage control in integrated circuit devices.